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Title: A Study of B0 to rho+rho- Decays and Constraints on theCKM Angle alpha

Abstract

The authors present results from an analysis of B{sup 0} {yields} {rho}{sup +}{rho}{sup -} decays using (383.6 {+-} 4.2) x 10{sup 6} B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The measurements of the B{sup 0} {yields} {rho}{sup +}{rho}{sup -} branching fraction, longitudinal polarization fraction f{sub L}, and the CP-violating parameters S{sub long} and C{sub long} are: {Beta}(B{sup 0} {yields} {rho}{sup +}{rho}{sup -}) = (25.5 {+-} 2.1(stat){sub -3.9}{sup +3.6}(syst)) x 10{sup -6}, f{sub L} = 0.992 {+-} 0.024(stat){sub -0.013}{sup +0.026}(syst), S{sub long} = -0.17 {+-} 0.20(stat){sub -0.06}{sup +0.05}(syst), C{sub long} = 0.01 {+-} 0.15(stat) {+-} 0.06(syst). The authors determine the unitarity triangle angle {alpha}, using an isospin analysis of B {yields} {rho}{rho} decays. One of the two solutions, {alpha} = [73.1, 117.0]{sup o} at 68% CL is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry based approach.

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
907715
Report Number(s):
SLAC-PUB-12498
arXiv:0705.2157; TRN: US0703365
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review D
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ISOSPIN; POLARIZATION; STANFORD LINEAR ACCELERATOR CENTER; SYMMETRY; UNITARITY; Experiment-HEP,HEPEX

Citation Formats

Aubert, B. A Study of B0 to rho+rho- Decays and Constraints on theCKM Angle alpha. United States: N. p., 2007. Web.
Aubert, B. A Study of B0 to rho+rho- Decays and Constraints on theCKM Angle alpha. United States.
Aubert, B. Wed . "A Study of B0 to rho+rho- Decays and Constraints on theCKM Angle alpha". United States. doi:. https://www.osti.gov/servlets/purl/907715.
@article{osti_907715,
title = {A Study of B0 to rho+rho- Decays and Constraints on theCKM Angle alpha},
author = {Aubert, B.},
abstractNote = {The authors present results from an analysis of B{sup 0} {yields} {rho}{sup +}{rho}{sup -} decays using (383.6 {+-} 4.2) x 10{sup 6} B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The measurements of the B{sup 0} {yields} {rho}{sup +}{rho}{sup -} branching fraction, longitudinal polarization fraction f{sub L}, and the CP-violating parameters S{sub long} and C{sub long} are: {Beta}(B{sup 0} {yields} {rho}{sup +}{rho}{sup -}) = (25.5 {+-} 2.1(stat){sub -3.9}{sup +3.6}(syst)) x 10{sup -6}, f{sub L} = 0.992 {+-} 0.024(stat){sub -0.013}{sup +0.026}(syst), S{sub long} = -0.17 {+-} 0.20(stat){sub -0.06}{sup +0.05}(syst), C{sub long} = 0.01 {+-} 0.15(stat) {+-} 0.06(syst). The authors determine the unitarity triangle angle {alpha}, using an isospin analysis of B {yields} {rho}{rho} decays. One of the two solutions, {alpha} = [73.1, 117.0]{sup o} at 68% CL is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry based approach.},
doi = {},
journal = {Physical Review D},
number = ,
volume = ,
place = {United States},
year = {Wed May 16 00:00:00 EDT 2007},
month = {Wed May 16 00:00:00 EDT 2007}
}
  • We present results from an analysis of B{sup 0}{yields}{rho}{sup +}{rho}{sup -} decays using (383.6{+-}4.2)x10{sup 6} BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The measurements of the B{sup 0}{yields}{rho}{sup +}{rho}{sup -} branching fraction, longitudinal polarization fraction f{sub L}, and the CP-violating parameters S{sub long} and C{sub long} are as follows: B(B{sup 0}{yields}{rho}{sup +}{rho}{sup -})=(25.5{+-}2.1(stat){sub -3.9}{sup +3.6}(syst))x10{sup -6}, f{sub L}=0.992{+-}0.024(stat){sub -0.013}{sup +0.026}(syst), S{sub long}=-0.17{+-}0.20(stat){sub -0.06}{sup +0.05}(syst), C{sub long}=0.01{+-}0.15(stat){+-}0.06(syst). We determine the unitarity triangle angle {alpha}, using an isospin analysis of B{yields}{rho}{rho} decays. One of the two solutions, {alpha}=[73.1,117.0] deg. at 68% confidence level, ismore » compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry-based approach.« less
  • Using a data sample of 89 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC, the authors measure the B{sup 0}({bar B}{sup 0}) {yields} {rho}{sup +}{rho}{sup -} branching fraction as (30 {+-} 4(stat) {+-} 5(syst)) x 10{sup -6} and a longitudinal polarization fraction of f{sub L} = 0.99 {+-} 0.03(stat){sub -0.03}{sup +0.04}(syst). They measure the time-dependent-asymmetry parameters of the longitudinally polarized component of this decay as C{sub L} = -0.17 {+-} 0.27(stat) {+-} 0.14(syst) and S{sub L} = -0.42(stat) {+-} 0.14(syst). They present constraints on the CKM angle {alpha}.
  • A precise measurement of the angle {alpha} in the CKM triangle is very important for a complete test of Standard Model. A theoretically clean method to extract {alpha} is provided by B{sup 0} {yields} {rho}{pi} decays. Monte Carlo simulations to obtain the BTeV reconstruction efficiency and to estimate the signal to background ratio for these decays were performed. Finally the time-dependent Dalitz plot analysis, using the isospin amplitude formalism for tre and penguin contributions, was carried out. It was shown that in one year of data taking BTeV could achieve an accuracy on {alpha} better than 5{sup o}.
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